We perform a topological analysis of chaotic signals from a Nd-doped fiber laser with pump modulation at different values of the modulation frequency. In this experiment, the system displays chaotic behavior in three regions C 1/4 , C 1/3 , and C 1/2 of parameter space, located around the subharmonics r /4, r /3, and r /2 of the relaxation frequency r . We observe that the topological structures of the chaotic regimes inside a given region C 1/n are described by the same template. However, templates corresponding to different regions display different global torsions g , which we find to be related to the order of the subharmonics by g (C 1/n )ϭnϪ1. ͓S1063-651X͑97͒09804-8͔ PACS number͑s͒: 05.45.ϩb, 42.65.Sf, 42.55.Wd *Electronic address: Guillaume.Boulant@univ-lille1.fr † Electronic address: Marc.Lefranc@univ-lille1.fr ‡ Electronic address: Serge.Bielawski@univ-lille1.fr § Electronic address: Dominique.Derozier@univ-lille1.fr